The latest measurements of phosphorous and nitrogen levels in the White River concern the man who is responsible for providing drinking water to most of Northwest Arkansas.
The threat to Beaver Lake isn't immediate, but the trend is in and it's not good, said Lane Crider, chief executive of the Beaver Water District. Nitrogen also worsens water quality, he said.
Eroding water quality can cause increased water treatment costs, he said.
The upper reaches of the White River watershed -- the shallowest, most vulnerable part -- feed Beaver Lake. Beaver Lake through the Beaver Water District provides drinking water to the major cities of Northwest Arkansas, ultimately reaching about 400,000 customers including the region's major industries.
The state measures the amount of phosphorous and nitrogen, among other material, carried along by the White River. The river flows almost all the way through Arkansas, starting in the Boston Mountains, curving through southern Missouri and descending through north and east Arkansas before flowing into the Mississippi River.
The Arkansas Natural Resources Division is working on a website showing the phosphorous and nitrogen "loadings," along with other data, for every watershed in the state. The site isn't finished, but the division agreed to share figures from the site Friday.
Those figures show a nitrogen "load" of at least 11.6 million pounds a year in 2019 in the portion of the White River watershed that flows into Beaver Lake, up from 8.9 million pounds in 2014.
Phosphorus carried by the river in the watershed was more than 1.9 million pounds in 2019 compared with 1.4 million in 2014.
Phosphorus is a major food for algae blooms and a type of algae known as blue algae can contaminate water, rendering it unfit for drinking.
The upper reaches of the river are more vulnerable, Crider said.
"Further down, these elements have time to settle to the bottom and there's greater volume of water," he said. The cliche "the solution to pollution is dilution" has a lot of truth to it, but Beaver Lake has less volume of water to work with, he said.
These trends can be reversed, said both Crider and Becky Roark, executive director of the Beaver Watershed Alliance, a nonprofit group encouraging protection of the watershed.
Crider pointed to success in reducing phosphorus levels in the Illinois River -- a process spurred in part by a lawsuit and other disputes brought by Oklahoma. The Illinois also starts in Northwest Arkansas, but flows west into Oklahoma.
Crider's best guess of where the increased nitrogen and phosphorus levels are coming from is land application of residues left over from industrial and commercial wastewater treatment being spread as fertilizer on fields.
"I don't think it's poultry litter," he said.
The region's poultry industry has made great strides in removing litter from the area's watersheds, he said, but the district still sees new applications with state regulators regularly for spreading other residue, he said.
Landowners are becoming increasingly aware of problems with runoff and erosion from their property, Roark said in an telephone interview Wednesday.
"I know one property owner who's lost 4 acres off of one property because of erosion," she said.
Property owners are becoming aware that measures such as leaving riparian buffers -- trees and other plants along streams -- save more than they cost while reducing pollutants reaching rivers, she said.
"People used to clear land all the way down to the banks," Roark said. Now they are much more interested in tax credits and other incentives for leaving up buffer areas, she said.
The alliance holds forums on watershed protection issues, with the next scheduled from 11:30 a.m. to 1:30 p.m. July 13 at the Fayetteville Public Library's Zeigler Room. The forum's topic is on planning and zoning codes -- laws that need revising, she said.
"We're not antidevelopment," Roark said. "What we need is to reimagine how we develop, to put ways to soak in water into our codes and policies for cities and counties. There are case studies for low-impact development," she said.
Leaving up buffer zones and providing areas where rainwater can still soak into the ground can stop runoff and the dissolved nitrogen and phosphorus in it even if the runoff is from some place farther uphill from the property with the buffer, she said.
"We're at a pivotal moment but we have simple tools utilized in other cities," Roark said. "There's a whole suite of tools available."
Northwest Arkansas meets its challenges and will meet this one in the Beaver Lake watershed, 3rd District Rep. Steve Womack, R-Ark, said. The region's residents and its industry are acutely aware of the importance of the lake, he said.
"I've been all over this country and have seen how alert people are here to the needs of the environment," Womack said. "Look at the Illinois River Partnership," a nonprofit organization based in Cave Springs. It contributed heavily to reducing phosphorous levels in the Illinois River and reducing the rancor over the issues involved among the stakeholders, he said.
"That level of cooperation is something that causes Northwest Arkansas to stand out."